Hydraulically operated cylindrical grinding machine



Dec. 12, 1939. I c, Q FLYGARE 2,183,490

HYDRAULICALLY OPERATED CYLINDRICAL GRINDING MACHINE Filed July l5, 19392 Sheets-Sheetl 1 az si:

IIHIIII Il Cam. EJrLYEFfm- @Mmmm lDevx. l2, 1939. ne. FLYGAREHYDRAULICALLYl QPERATD CYLlNDRICAL GRINDING MACHINE Filed July 15. 19592 sheetssheet 2 Patented Dee. 12, 1939 HYDBALICALLY ori-:RATEDGYLINDBICAL GRINDING MACHINE Carl G. Flygare, Worcester, Mass., assignerto Norton Company, Worcester, Mass., a corporay tion of MassachusettsAppucauoouiy 15, 193s, serial No. zsassvs s claims.

The invention relates to grinding machines, and more particularly to anelectrically controlled .hydraulically .operated cylindrical typegrinding-machine.

One object of the invention is to provide an improved electricallycontrolled, hydraulically operated grinding machine with animprovedcycle control mechanism. A further object of the invention is toprovide an interlocked control for a grinding machine Wheel feedmechanism, a footstock, and a work ejecting mechanism. A further objectof the invention is to provide a hydraulically operated grinding machinewith an improved electrical control mechanjsm,

A further object of the invention is to-provide a cyclic wheel feedingmechanism which is electrically interlocked with the footstock so thatthe wheel cannot be advanced until the footstock center is in anoperative position. Another .ob-

ject ofthe invention is to provide an electrical interlock between theWork ejector mechanism and the other mechanisms lof the ymachine wherebyIthe wheel feed and the footstock controls are rendered inoperativeduring the work unloading and loading operations. Other objects will bein part obvious or in part pointed out hereinafter.

t The invention accordingly consists in the features of construction,combinations of elements and arrangements of parts, as will beexemplified in the structure to be hereinafter described, and

the scope of the application of which will be indicated in the followingclaims.

In the accompanying drawings, in which is shown one of various possibleembodiments of the mechanical features of this invention,

Fig.- 1 is a front elevation of the improved grinding machine;

Fig. 2 is a longitudinal sectional view through the headstock andfootstock and through the hydraulic wheel feed mechanism combined withan electrical and hydraulic diagram to illustrate the operative cycle ofthe machine;

Fig. 3 is a longitudinal sectional view, on `an enlarged scale, throughthe footstock, showing thegelectrical interlock and control mechanism;and

4 is a fragmentary longitudinal sectional view, on an enlarged scale,through the headstock, showing the work ejector-mechanism.

. A grinding machine has been illustrated in the drawings which is ofthe same/ general type as `that shown in the prior U. S. patent to WoodNo. 2,071,677 dated February 23, 1937. A grinding machine has4 beenillustrated in the draw- -ings comprising a base III which supports alongitudinally reciprocable work supporting table II on the usual V-wayand' at way (not shown).. The work table II may be traversed longitudi-5 nally either manually or by power by any of the well knownmanual orpower operated. mechanisms. As illustrated in the drawings, a manuallyoperable traverse mechanism has been il1 istrated comprising a rack vbarI2 depending 10 from the'table II which meshes with a gear I3. The gearI3 is rotatably supported within the base I0 of the machine. A gear I4is mounted and arranged to rotate with the gear I3 and meshes with agear I5 mounted on the inner end l5 of a rotatable shaft I6. A manuallyoperable hand traverse wheel I1 is mounted on the outer end of the shaftI6. By rotating the hand wheel I1 in either direction, the worksupporting table I I maybe traversed longitudinally in the desired 20direction.

.Power traverse The table II may, if desired, I'be reciprocatedlongitudinally by a power operated mechanism, such as that shown in theprior U. S. Patent No. 25 2,071,677 above referred to, to whichreference may be had for details of disclosure not contained herein. Thepower operated table traverse mechanism is preferably a fluid pressuremechanism comprising a cylinder 20 which is fixe'dly mounted to theunderside of the table I I. The cylinder 20 contains a pair of spacedpistons (not shown) which are connected by a pair of hollow connectingrods 2| and 22 to a pair of hollow brackets 23 and 24, respectively,which 35 are fixedly mounted on opposite ends of the base I0.

The base III is formed as a hollow box-like construction, the lowerportion of which'serves as a iiuid reservoir 25 for the iiuid pressuresystem. Fluid is drawn from the reservoir 25 through a pipe 26 by meansof.a motor driven iiuid pump 21 and is forced through a pipe 28 to atable control valve 29. A fluid pressure reu lief valve 30 is connectedin the pipe line 28 which is arranged to allow fluid under pressure ,toby-pass through a pipe 3| into the reservoir valve29 'is also connectedby means of a pipe 55 86 with the bracket 24 which forms a huidconnection with a cylinder chamber at the righthand end of the cylinder20. By actuating ythe control valve 29, the table il may be caused' totraverse in either direction, as desired. The control valve has not beenillustrated in detail in the present case since it is not considered tobe a part of the present invention. For further details of thetablecontrol valve 28, reference may be had to the above-mentioned priorPatent No. 2,071,677.

A table actuated reversing lever 88 is pivotally mounted on the front ofthe machine base and is operatively connected to actuate the tablecontrol valve. A pair of adjustable table dogs 88 and 40 are adjustablysupported by a V-slot formed in the front edge of the table il and serveautomatically to actuate the lever 88to shift the control valve 29.

The speed of reciprocation of the table Il is controlled by means of aspeed control valve (not shown) which is actuated by movement of thecontrol lever 38 toward and from the front of the machine. This valveand its connections with the lever 38 are clearly disclosed in theabove-mentioned prior patent.

As illustrated in the drawings, the base I0 also supports a rotatablegrinding wheel 45 which is. supported on one end of a rotatable wheelspindle (not shown) which is journalled in bearings carried by atransversely movable wheel slide 46. The grinding wheel 45 may be drivenin any suitable manner such as, for example, by means of an electricmotor 41 mounted on the upper surface of the wheel slide 46. The motoris provided with a shaft 48 which supports a pulley 49 which is in turnconnected by means of a belt 50 with a pulley 5I mounted on therighthand endof the wheel spindle (Fig. l).

The work supporting table il serves as a support for a rotatable worksupporting mechanism comprising a headstock 50 which is provided with arotatable headstock spindle 5|. The spindle 5| is provided at itsright-hand end with a work supporting center or chuck 52, which in thepresent case has been illustrated as a female center, to engage andsupport a frusto-conical end portion of a work piece 53. The spindle 5Iis rotated by means of an electric motor 54 mounted on the upper surfaceof the headstock 50. 'Ihe motor 54 is provided with a driving pulley 55which is of the multiple V-groove type. The pulley 55 is connected by amultiple V-belt 56 with a multi-grooved pulley 51 mounted on thelefthand end of the headstock spindle 5I (Fig. 2).

The other end of the work piece 53 is supported by means of a footstock60. The footstock 68 is provided with a longitudinally movable spindle6| which is provided at its outer end with a footstock center 62 whichis arranged to rotatably support the right-hand end of the work piece53. The footstock spindle 6I is preferably moved to and from anoperative position by means of a fluid pressure mechanism comprising acylinder 83 having a piston 64 slidably mounted therein. A spring 65 isinterposed between the piston and the footstock spindle .6| and isarranged to yieldably maintain the footstock center 62 in operativeengagement with the work piece 58 during the grinding operation. -Fluidmay be admitted through the pipe 66 into a cylinder chamber 61 to causethe piston 64 and the spindle 6| together with the footstock center 62to move toward the left (Fig. 2) into an operative position or, ifdesired, fluid under pressure may be admitted through a pipe 88 into acylinder chamber 88 to cause the piston 64 and footstock center 82 tomove to an inoperative position. The fluid pressure system and thecontrol mechanism therefor will be"descrlbed hereinafter.

An interlock ls provided to prevent the grinding wheel from starting itsforward feeding movement until the work center 62 is in an operativeposition. A normally open limit switch 15 is interconnected with thewheel feeding mechanism in a manner to be hereinafter described. A lever16 is pivotally mounted on a stud 11 which is fixedly supported on thefootstock 68. The lower end of the lever 18 is arranged in the path of aslidably mounted rod 18 which is slidably supported by a stationary partof the footstock 88. When the footstock piston 64 moves toward the left(Fig. 3) to move the footstock center 62 into supporting engagement withthe end of the work piece 53, the piston 84 engages the end of the rod18 and moves it endwise toward the left. This movement of the rod 18serves to rock the lever 16 in a clockwise direction against thecompression of a spring 18. During the clockwise movement of the lever16, it engages the actuating roller of the limit switch 15, which servesto close the limit switch 15 only when the piston 64 and the footstockcenter 62 are moved into an operative position.

Work ejector The headstock 50 is provided with a work ejector mechanismwhich is arranged automatically to eject the work piece 58 from thefemale cen? ter 52. As illustrated in the drawings, the ejecis iixedlysupported on the end of the piston' rod 84. A spring 81 surrounds thepiston rod 84 and is interposed between the piston 85 and the left-handend of the cylinder 86 which serves normally to hold the piston and theejector rod 88 in an inoperative position, as illustrated in Fig. 2. Theejector rod is moved to eject the work piece 53, by means of a iluidpressure mechanism. Fluid under pressure is admitted through a pipe 88into a cylinder chamber 89 to 'move the piston 85 and piston rod 84toward the left (Fig. 2), which movement serves to rock the lever 82 ina clockwise direction.' AThe clockwise movement of the lever 82 servesto move the ejector rod toward the right (Fig. 2) to eject the workpiece 53 from the female center 52.

A work supporting or loading cradle 88 is mounted on the table il andserves to support the work piece 53 during the loading and electingoperations.

Wheel feeding mechanism A wheel feeding mechanism is provided to controlthe feeding movement and adjustment of the grinding wheel 45 toward andfrom the work support. The wheel slide 48 is provided with a dependinghalf nut 85 which meshes with a rotatable cross feed screw 86. The feedscrew 86 is rotatably supported in bearings 81 and, in the base i8. Thefeed screw 88 may be rotated manually for adjusting the position of.

the wheel slide 46 in setting up the machine,

by a manually operable feed lmechanism to be hereinafter described. L

In order that the wheel slide 46 may be rapidly moved toward the workpiece 53 to grind the same, the feed screw 96 is connected to a pistonrod 99. A fluid pressure cylinder is arranged in axial alignment withthe feed screw 96 and contains a slidably mounted piston |0| which isconnected with the piston rod 99. The uid pressure pump 2l forces -fluidthrough the pipe 28 to a feed control valve 02. The feed control valve|02 is preferably of the piston type, comprising a valve stem |03 havinga plurality of valve pistons formed `integrally therewith. This fluidpressure feeding mechanism,'as illustrated in Fig. 2, is substantiallyidentical to that shown inthe prior U. S. patent to Cole and Amidon No.2,101,790 dated December '1, 1937, to which reference may be had fordetails of disclosure not contained herein. In the position of the feedcontrol valve |02 (Fig. 2), fluid under pressure passing through thepipe 28 enters a valve chamber |04 and passes through a passage into acylinder chamber .|05 formed at the lefthand end of the cylinder |00(Fig. 2) to cause the piston |0I, the wheel slide 46, and the grindingwheel 45 to move into a rearward or inoperative position.A During thisrearward feeding movement of the grinding wheel, fluid is exhausted froma cylinder chamber |06 formed at the right-hand end of the cylinder |00(Fig. 2), through a passage, and through a valve chamber |01, and outthrough a-pipe |08 which exhausts into the reservoir 25.

The forward end of the valve stem |03 is pivotally connected to the.upper end of a lever |09 which is pivotally supported on a fixed stud||0. A spring is connected between the lower end of the lever |09 and afixed stud ||2 and serves normally to hold the feed control valve |02 inthe position illustrated in Fig. 2 to move and hold the grinding wheel45 and its supporting slide 46 in its rearward or inoperative position.A solenoid ||3 yis connected to the lower end of the lever |09 and isarranged so that when energized, it rocks the lever |09 in acounterclockwise direction, moving the valve stem |03 toward the left(Fig. 2) to shift the control valve |02 also toward the left so as toadmit uid under pressure passing through the pipe 28 and valve chamber|04 into the cylinder chamber |06 to cause a forward feeding movement ofthe grinding wheel 45. The admission of fluid under pressure to'thecylinder chamber |06 produces a rapid forward movement of the grindingwheel 45.

Dash pot of the work piece 53 being ground. As illustrated in Fig. 2, anoutwardly extending casing |5 is fixedly mounted .to the end of thecylinder |00 and contains a pair of diametrically arranged spaced dashpot pistons ||6 and which slide within dash pot cylinders formed withinthe casing |I5. The dash pot pistons ||6 and normally are held in arearward position by means of springs. During the rapid approach of thegrinding wheel 45, the dash pot pistons are inoperative. The piston rod99 extends toward the rear of the machine and is provided at preachingmovement continues until an adjustable collar |23, carried by a threadedend portion |24 of the piston rod 99, engages the end of the sleeve |20.'I'he continued movement of the piston |0| is resisted by the dash potpistons H6 and Il'l, which force fluid under pressure from the dash potcylinders through an adjustable needle valve |25 into a reservoir |26.By adjustment of the needle valve |25, the exhaust of uid from the dashpot cylinders may be readily controlled to produce the desired grindinginfeed, so that the grinding wheel will be moved into the Work piece togrind the same at the desired rate of speed. This dash pot mechanism issubstantially the same as that shown in the prior U. S. patent to ColeandAmidon No.

. 2,101,970 dated December 7, 1937, and since this feature is notconsidered to be a part of the present invention, the details ofdisclosure have not been completely described herein. For details of-disclosure not contained herein, reference may be had to the priorpatent above mentioned.

The fluid reservoir '|26 and the dash p'ot cylinders form a separatefluid system which is independent of the main feed cylinder |00. Inorder to ll the reservoir |26, a pipe |21 is connected with the fluidpressure pipe 28 which leads from the fluid -pump 21, and a manuallyopera/ble valve |28 in the pipe line |21 serves to admit fluid from thepump into the reservoir |26 to ll the dash y pot system in settingv upthe machine `and to maintain it full during use. An overflow pipe |29 isprovided which is connected'with the exhaust pipe |08 to convey excessfluid from the reservoir |26 to the main reservoir 25. If desired, thevalve |28 may -be maintained lightly open 'during the use ofthe machine,o that the reservoir |26 will be at all times filled and any overflowtherefrom may readily return to the main reservoir 25. In order to allowthe dash p'ot cylinder chambers to fill rapidly as the wheel slide 46moves rearwardly, a ball check Valve |30 is. provided in the dash potcylinder casing I5 which is connected by means of a pipe I 3| with thereservoir |26. By providing the ball check valve |30, fluid is quicklyadmitted into the dash -pot cylinders instead of being drawn whollythrough the needle valve |25.

Positive stop In order to grind the work piece 53 to a predeterminedsize, it is necessary to feed the grinding wheel 45 toward the workpiece 53 to grind the same and then to stop the infeed and allow thegrinding wheel 45 to grind out or to allow the sparks to die out `inorder to round up or finish grind the work so that it will be ground toa true cylindrical surface of a predetermined size. As illustrated inthe drawings, a positive stop sleeve |32 surrounds and is adjustablysupported on the sleeve |20 and is arranged to engagea dash pot cylinderhead when the grinding wheel has advanced to a predetermined positionpositively to stop the forward advance of the Y/wheel for a flnishgrinding operation.

Manual feed adjustment shaft |44 is journalled in suitable bearingsk(not shown) in the base |0. The shaft |44 carries at its forward end agear |45 which meshes with a small gear (not shown) which is supportedto rotate with a manually operable feed wheel |46. The feed screw 96 maybe rotated manually by rotation of the manually operable feed wheel |46in either direction to adjust the position of the wheel slide 46 and thegrinding wheel 45. A reciprocable feed pawl |41 is provided forintermittently actuating the feed wheel |46 at the ends of the tablestroke when the machine is set up for a traverse grinding operation.'I'he feed wheel |46 is provided with a manually operable micrometeradjusting mechanism' |48.to facilitate adjustment of a stop abutmentwhich is carried by the feed Wheel |46 and is arranged to engage thefeed pawl |41. This mechanism has not been illustrated in detail. sinceit is not considered to be a part of the prisent invention. Referencemay be had to the prior U. S. patent "to Norton No. 762,838 dated June14, 1904, for

details of disclosure not contained herein.

'I'he fluid pressure pump 21 also supplies uid under pressure foractuating the footstock 60. A solenoid valve is provided for controllingthe passage of uid under pressure to operate the footstock. 'I'he valve|60 is preferably a piston type valve having a plurality of valvepistons |6|, |62 and |63 formed integral with the valve stem. A solenoid|64 is connected to the upper end of the valve stem and serves whenenergized to shift the valve in an upward direction. A spring |65surrounding the valve stem and interposed be-` tween the valve piston|6| and the end of the valve casing serves normally to hold the valvein. a downward position. Fluid under pressure from the pump passingthrough the pressure pipe 28. Passes through a pipe |66 into a valvechamber located between the valve pistons |62 and |63 and passes outthrough the pipe 68 into the cylinder chamber 69 to move the footstockcenter 62 toward the right into an inoperative position, gs shown inFig. 2. During this movement of the footstock center 62, fluid isexhausted from the cylinder chamber 61 through the pipe 66 into a valvechamber located between the valve pistons |6| and |62 and exhauststhrough a pipe |66 into the main reservoir 25. When the solenoid |64 isenergized, the valve pistons |6I, |62, and |63 move upwardly so thatfluid under pressure passing through the pipe |66 into the valve chamberbetween the 4valve pistons |62 and |63, passes through the pipe 66 intothe cylinder chamber 61 to move the piston 64 and footstock center 62toward the left into an operative position to support the right-hand endof the work piece 53.

During this movement of the footstock center l2 into an operativeposition, fluid within the cylinder chamber 68 exhausts through the pipe68 and passes out through a pipe or passage |88 into the pipe |68 whichin turn exhausts into the main reservoir 26.

The ejector mechanism is similarly actuated by fluid under pressure fromthe pump 21'. The passage of fluid to the ejector mechanism iscontrolled by a solenoid valve |10 which is preferably a piston typevalve comprising valve pistons |1|, |12 and |13. An electric solenoid|14 is connected to the upper end of the valve stem and serves whenenergized to shift the valve in an Yupwar'd direction. A spring |15which surrounds the valve stem and is interposed between the valvepiston |1| and the end of the valve casing, serves normally to hold thevalve in a downward position. Fluid under pressure from the pump 21passing through the pipe 28 also passes through a pipe |16 into a valvechamber located between the valve pistons |12 and |13. In the positionof the valve (Fig. 2), nothing happens. The cylinder chamber 86 isconnected by the pipe 88 with a valve chamber located between the valvepistons |1| and |12 which, as illustrated, is connected by a pipe |18which exhausts fluid into the main reservoir 25.` When the solenoid |14is energized, the valve pistons |1|, |12 and |13 are moved upwardlyagainst the compression of the spring |15 so that lfluid under pressurepassing from the pipe |16 into the valve chamber located between thevalve pistons |12 and |13, passes through the pipe 88 into the cylinderchamber 88 to cause the piston-85 and the piston rod 84 to rock thelever 82 in a clockwise direction, which in turn shifts the ejector rodtoward the right (Fig. 2) to eject the workpiece 68 from the femalecenter 52.

The improved grinding machine is provided with an interlock whichprevents a forward feeding movement of the grinding -wheel until thefootstock center 62 is in supporting engagement with the work.Similarly, the footstock center is interlocked so that it cannot bewithdrawn from supporting engagement with the work until the wheel slidehas moved to its rearward position. In the preferred construction anelectrical interlock is provided. The machine receives its source ofpower from the power lines indicated diagrammatically (Fig. 2). Amanually operable push button switch 8| is provided for starting thegrinding cycle. The electrical circuit is arranged so that the pushbutton switch must be held closed until the grinding wheel 45 and itssupporting slide 46 have started on the forward approaching or feedingmovement. The closing of the push button switch |8| energizes a solenoid|82 of a mechanical latch-in electrical reset relay, such as thatmanufactured by the Struthers Dunn Inc. of Philadelphia, Pa. Theenergizing of the solenoid |82 closes a switch |83 which is normallyheld open by means of a spring |84. When the switch moves downwardlyinto a closed position, a spring-pressed latch |85 engages a projectinglug |86 on the switch plunger and locks the switch |83 in an operatingposition. The closing of the switch |83 serves to energize the solenoid64 to shift the footstnck control valve |60 upwardly so as to admit uidunder pressure through the pipe 66 into the cylinder chamber 61 to causethe footstock center to move into supporting engagement with the workpiece 53.

When the piston 64 reaches the end of its operative stroke, the rod 18acting upon the pivotally mounted lever 418 closes the normally openlimit switch 19 which in turn sets an electrical time delay relay |81 inmotion. The time delay relay |81, as illustrated, is one of the wellknown electrical time delay automatic reset relays, such as thatvknownas the Microex instantaneous reset timer relay manufactured by EagleSignal Corporation of Moline, Illinois, and which is covered by U. S.Patent No. 1,794,762 to J. A. Garell, to which reference may be had fordetails of disclosure not contained herein. The relay |81 is connectedto energize the feed control solenoid III which in turn shifts the feedcontrol valve |02 to initiate a forward feeding movement of the grindingwheel 45. A compression spring |88 serves to hold the latch |85 in anoperating position. 'Ihe latch |85 is arrangedto be automaticallywithdrawn at the desired time.

A pair of normally open limits switches |90 and |9| are providedadjacent to the rear end of the piston rod 99 and are arranged to beactuated by means of a cam or dog |92 which is adjustably supported onthe threaded end portion |24 of the piston rod 99 and serves in a mannerto be hereinafter described to aid in the interlocking of a variousmechanisms of the machine.

The manually operable starter push button |8| must be held in a closedposition until the footstock center 62 is in supporting engagement withthe work piece and the wheel starts its forward feeding movement, andmust be held closed until the dog or cam |92 rides off the actuatingroller of the normally open limit switch |9| so that the switch |9|opens to break the circuit, thus rendering a solenoid |94 which operatesthe latch |85 inoperative.

The forward feeding movement of the grinding wheel 45 continues for adefinite time interval, as controlled by the adjustable time delay relay|81', which serves after the said time interval automatically to breakthe circuit so as to deenergize the solenoid ||3, thus releasing thecompression of the spring ||"which shifts the feed control valve |02into its rearward position to cause a rearward movement of the Agrindingwheel.

. When the wheel approaches the forward end of its stroke, the cam ordog |92 on the rear end of the piston rod 99 engages the actuatingroller of the normally open limit switch |80 which serves to break acircuit, thus deenergizing a solenoid |95 which allows the releasedcompression of a spring |96 to withdraw a latch |91 from engagement withthe lug |98. The withdrawal of the latch |91 releases the compression ofa spring |99 which moves the switch member 200 of the mechanicallatch-in electrical reset relay into a closed position, thus closing thecircuit which is connected to the solenoid |94. The solenoid |94,however, is not energized since the normally open limit switch |9| isconnected in series therewith. The switch 200 remains in a closedposition until the wheel slide moves to its rearward position and thecam or dog |92 again engages the actuating roller of the normally openlimit switch |9| which closes the circuit, thus energizing the solenoid|14 to shift the ejector control valve |10 upwardly to admit uid underpressure through the pipe 88 into the cylinder of a normally open limitswitch 202 whichcloses a circuitv to energize a solenoid 203' whichopensV the switch 200,. When the solenoid |14 of the valve |10 isenergized, the solenoid |94 of the switch |83 which is kconnected inseries therewith is also energized to withdraw the latch |85, and thereleased compression of thesprlng |84 opens the switch 83. 'I'his inturn deenerg'izes the solenoid |64 to allow the valve |60 to drop intoits lower position, thus admitting fluid under pressure to withdraw thefootstock center 62 from supporting engagement with the work just priorto the actuation of the ejector spindle 80 in ejecting the work piece 53from the center 52.

It is desirable to provide means for stopping the grinding cycle at anytime and returning the respective parts to their initial positions. Inorder to accomplish this result, a manually operable switch, suchl as apush button stop switch 205, is connected ln the electrical circuit sothat in case the machine does not function properly, the circuit can beopened to immediately return the grinding wheel 45 to its rearwardposition.

A manually operable control lever 206 is pivotally mounted on a stud 201which is in turn supported by a boss 208 projecting from the front ofthe machine base. When the upper end of the lever is moved toward theoperator, the lower end of the lever operates the push button 8| toinitiate a grinding cycle. If at any time during the grinding cycle, itis desirable to stop the grinding operation and remove the wheel fromthe work, the upper end of the lever.206 is moved toward the machinebase which serves to actuate the push button switch 205 immediately tostop the grinding cycle.

The operation oi this machine is readily apparent from the foregoingdisclosure. Assuming the parts to have been previously adjusted so thatthe desired grinding cycle may be obtained, a work piece 53 is placed inposition on the work supporting cradle 90 (Fig. 2) and itsfrusto-conical end is moved into engagement with the female center 52.The control lever 206 is then shifted voutwardly'at its upper end toactuate the main cycle control push button |8| which closes a circuit toenergize the solenoid |82 which closes the switch 83 and latches it in aclosed position. Closing of the switch |83 energizes the solenoid |64 toshift the footstock valve |60 and admit fluid under pressure to causethe footstock center 82 to move into supporting engagef ment with thework piece. The shifting of the footstock center into an operativeposition serves to close the normally open limit switch 15 which closesa circuit to set the time delay relay |81 in operation. The relay |81 isconnected so that when it is set in motion, the solenoid ||3 isenergized to shift the feed control valve |02 to cause a forward feedingmovement of the grinding wheel 45. The forward feeding movementcontinues for a predetermined time interval as governed by the timedelay relay |81. When the predetermined time interval has elapsed, thesolenoid ||3 is deenergized and the released tension of the springshifts the feed control fluid under pressure to move the footstockcenter 62 to an inoperative position out of engagement with the workpiece 53. The solenoid |14 is then energized to shift the valve |10 soas to admit fluid under pressure through pipe 8B into cylinder chamber89 to shift the ejector rod 80 to eject the finish ground work piece 53from the female center 52 onto the cradle. The finish ground work piece53 may then be removed from the work supporting cradle 90 and replacedwith a new work piece to be ground.

It will thus be seen that there has been provided by this inventionapparatus "in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany possible embodiments may be made of the above invention and as manychanges might be made in the embodiment above set forth, it is to beunderstood that all matter hereinbefore st forth or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

I claim:

l. In a grinding machine having a rotatable grinding wheel, atransversely movable slide therefor, a longitudinally movable table, arotatable work support thereon including a headstock and footstock eachhaving a work supporting center, means including an electrical timedelay relay to cause a forward and rearward movement of the wheel slide,manually operated electrically controlled means to move said footstockcenter to an operative position, and an electrical control actuated bymovement of the footstock center to an operative position to initiate aforward feeding movement of the grinding wheel.

2. In a grinding machine having a rotatable grinding wheel, atransversely movable slidetherefor, a longitudinally movable table, arotatable work support thereon including a headstock and a footstockeach having a work supporting center, means including an electrical timedelay relay to control the transverse movement of said wheel slide, ahydraulic piston and cylinder to move said footstock center toward andfrom an operative position, a manually operated electrically controlledmeans to .control said piston and cylinder so as to cause the footstockcenter to move to an operative position, means including an electricalswitch actuated by movement of the footstock center to an operativeposition to initiate a forward feeding movement of the grinding wheel.

3. In a grinding machine having a rotatable grinding wheel, atransversely movable slide therefor, a longitudinally movable table, arotatable work support thereon including a headstock and a footstockeach having a work supporting center, a hydraulic piston andl cylinderto move said slide transversely, means including a electrical time delayrelay to control the extent of the forward feeding movement of saidslide, a hydraulic piston and cylinder to move said footstock centertoward an operative position, a manually operated electricallycontrolled means to control said piston and cylinder so as to cause thefootstock center to move to an operative position, and means includingan electrical switch operated by movement of the footstock to anoperative position to initiate a forward feeding movement of thegrinding wheel.

4. In a grinding machine having a rotatable grinding wheel, atransversely movable slide therefor, a longitudinally movable table, arotatable work support thereon including a headstock and a footstockeach having a work supporting center, a hydraulically operated pistonand cylinder to move said slide transversely, a control valve therefor,means including an electrically operated time delay relay to actuatesaid valve to initiate and control a grinding cycle, a hydraulicallyoperated piston and cylinder to move said footstock center toward andfrom an operative position, a control valve therefor, a manuallyoperated electrically controlled means to shift said valve to move thefootstock center to an operative position, and means including anelectric switch actuated by the movement of the footstcck center to anoperative position to shift said feed control valveto initiate a forwardfeeding movement of the slide and to render said time delay relayoperative so as to control the grinding cycle.

5. In a grinding machine having a rotatable grinding wheel, atransversely movable slide therefor, a longitudinally movable table, arotatable Awork support thereon including a headstock and a footstockeach having a work supporting center, a hydraulic piston and cylinder tomove the slide transversely, a control valve therefor, means includingan electric solenoid to' actuate said valve to produce Va forwardfeeding movement of the slide, means including an electrically operatedtime delay relay to control the extent of forward movement of the slide,a hydraulic piston and cylinder to move said footstock center toward andfrom an operative position, a solenoid actuated valvetherefor, manuallyoperated Aelectrically controlled means to actuate said solenoid valveto move the footstock center to an operative position, and meansincluding an electric switch actuated by movement of said footstockcenter to an operative position to energize said solenoid and initiate aforward feeding movement of the grinding wheel and to set said timedelayrelay in motion.

6. In a grinding machine having a rotatable grinding wheel, atransversely movable slide therefor, a longitudinally movable table, arotatable work support therein including a headstock and a footstockeach having a work supporting center, a hydraulic piston and cylinder tomove said slide, a. control valve therefor which is normally held in aposition to cause a rearward movement of the slide, an electric solenoidto actuate said valve to initiate a forward feeding movement of theslide, an electrically operated time delay relay to control saidsolenoid, a hydraulic piston and cylinder to move the footstock centertoward and from an operative posiion, an electric solenoid controlledvalve therefor, a manually operated switch to control said .solenoidvalve to actuate said footstock center,

and an electrical interlock between said wheel slide and footstockcenter whereby the wheel slide actuating mechanism is renderedinoperative until the footstock center has shifted into an operativeposition.

7. In a grinding machine having a rotatable grinding wheel, atransversely movable slide therefor, a longitudinally movable table, arotatable work support thereon including a headstock and a footstockeach having a work supporting center, a rotatable work rotating spindlein said headstock to support said headstock center, a work ejectorslidably mounted within said cylinder, means including an electricaltime delay relay to control the transverse movement of the wheel slide,a piston and cylinder to move said footstock center toward and from anoperative position, a hydraulic piston and cylinder to actuate saidejector, means including a manually operable electrical control meansfor said footstock and ejector, and means including an electric `switchactuated by and in timed relation with the time delay relay to renderthe ejector operative to ejecta Work piece after a grinding operationhas been completed.

8. Ina grinding machine having a rotatable grinding wheel, atransversely movable slide therefor, a longitudinally movable table, arotatable work support thereon including a headstock and a footstockeach having a work supporting center, a rotatable Work rotating spindlein said headstock to support the headstock center, a Work ejectorslidably mounted Within said spindle, a hydraulically operated pistonand cylinder to move said wheel slide, means including an electricallyoperated time delay relay to con.-

trol the forward movement of the slide, a hy draulic piston and cylinderto move said footstock center toward and from an operative position, asolenoid actuated valve to control the admission of Iiuid to saidcylinder, a hydraulic piston and cylinder to actuate said ejector, asolenoid actuated valve to control the admission of iiuid to saidejector cylinder, a manually operated electrically controlled means toactuate the footstock solenoid valve to initiate a movement of thefootstock center to an operative posi- 'wheel slide, and electricallycontrolled means actuated by the time delay relay to operate saidejector solenoid valve to eject a work piece at the end of a grindingcycle.

CARL G. FLYGARE.

